Coal pulverizer



Qct. 2s, 1924. 1,513,279

F. sAwFoRD v GOAL PULVERIZER Flred June 12, 1923 2 Sheets-Sheet 1 F. SAWFORD COAL PULVERI ZER Filed June 12 1923 2 sugars-sneer 2 l IVENTQR Fran/E' Jawfofa ATTORNEY Patented Cct. 28, 1924.'

UNITED STATES rmx snwronn, or vancouver., anrrrsn commu, enum.

cou. runvnnlzna.'

Application nled June 12,

' To azz whom a my amm:

Be it known that 1,/FRANK SAwronn, citizen of the Dominion of Canada, residing at Vancouver, in the Province of British Columbia, Canada, have invented certain new and useful Improvements in Coal Pulverizers, of which the. following-is a specification. v

This invention relates to a system of pulverizing coal and for delivering it to a furnace for combustion withthe air by.- which the pulverized coal is separated. The full advantages derivable from the use of pulverized coal as a fuel are not at present attained, as the cost of drying, pul` verizin and sifting the coal dust to the requi v degree'of nene'ss involves, as at present practised, a lcapital outlay that *isv prohibitive in any except'large installation. In the invention, which is the subject of this application, the fuel is pulverized, not .by crushing, but by impact with beaters reat a hi h velocity, and the separavolvin tion o the coa dustwhen suiliciently fine is effected, not by screening, but by va draught of air, which air is used as the medium of conveyance of the coal dust to the furnace and is there consumed with it with such further supply of air as may be necessary -or desired.

MeansA is also provided for retaining the fuel exposed to the beaters until it is suffi-v v ciently1 fine to be carried away in the air draug t, and for regulating the amount of air, either hot or cold, delivered with the fuel to the furnace andthe amountof that air drawn through the pulverizer whereby the f ineness of the coal dust is regulated. This elimination of the requirements for crushing and screening dispenses with the need lfor drying the coal, which drying is more particularly necessary when the coal is to be crushed and screened, because even a small amount of moisture in the coal is a hindrance in that work but it not objectionable in combustion.

y'Ihe'impact pulverizer' and the air fan by which the separation of the coal dust is effected, and the means by which the -coal is fed to the pulverizer and the coal dust delivered tothe furnace for combustion with the air in which it is carried in suspension all constitute a selffcontained machine of small size and simple design and one which performs its work in an `eminently satisfactory manner.

1923. Serina-1K0. 644,949.

The invention vlis fully. described the l following: specification, `reference beingl made to the' ldrawings by which it is accoml panied, in which Fig. 1 is a. vertical longitudinal section. Figs. '2, 3, 4 and j5 are enlarged details fil-' 'lustrating the lining ring of the pulverizer.-

Fig. 6 1s a detail of the pulverizing wheel,

a part being in section to show the preferred l manner of securing the radial pin. r

Fig. v7.is a cross section of the pulverizer o n the line 7--7 .in Fig. 1 looking in the direction of the arrow.

l Fig. 8 is an end elevation of the centrif- 70 ugal fan and its casing removed from the pedestal support, and

' F'g.-9 shows the'means for driving the coal feed from the pulverizer shaft and of connecting the air control jdampers to. the

coal feed control.

In these drawings 2 represents the base of Athe machine on which are secured hollow pedestals 3 and 4' which carry. the bearings of the shaft l5 Aon which the pulverizer and S0 its air fan are secured and between which pedestals the casing 6 of the pulverizer and 7 of the fan are secured.

The pulverizer casing 6 is conically reduced toward each end from an intermediate `cylindrical portion adapted to receive a lining of hard metalpulverizing rings v8, the casin and rings bein diametrically halved andpjointedtogether 1n a horizontal plane. x! Each .ring '8 has an inwardly projecting 90 ridge 9, the inner surface of which is deeply corrugated, as shown in Fig. 2, and the sides l of the ridges 9 are correspondingly corrugated to a less depth as shown in Fig. V5, the

circumferential and lateral corrugations merging into one another. .v

In the spaces between the ridges 9 of these rings pass the pins -10 of wheels 11, which pins are secured in the'wheels At0 radially' project from their outeredges. Preferably the pins 10 are formed in pairs, each pair being bent from lone p'iece of round rod and the bend is cast in the wheel, as shown in Fig. 6.

A number of these wheels 11 with their 105 radially projecting pins 10 are keyed together on the .shaft 5 and at each end of the group is secured an open spoked wheel 13 having va rim which is coned lto conform to the'correspondi'ng part of the casing 6.

A hollow, cylindrical bushing 15 is Vse-v cured to the face of the pedestal 3 to pro#` ject within it concentric with the shaft and leave an annular space 16 surrounding the shaft. llnto the upper side of this bushing pro'ects the lower end of a chute 1 7 through w ich the coal to be pulverlzed 1s delivered from a feed. screw 18 rotatably mounted in the lower end of a hopper 19 secured to the up er side of the pedestal 3 and supported on t e upper side of the pulverizer casing 6.

The fan casing 7, which is in direct communication with the space within the pulverizer, is mounted between a circular flange the fuel to the furnace.

on the pulverizercasing and a corresponding flange on thepedestal 4 with the cavity of which the casing? is also in direct communication. Being mounted on two circular flanges, .enables the discharge 20 of the fan to be turned to any desired position or angle around the shaft that may be found convenient for connection to the furnace.

The wall of the pedestal 3 has an aperture 21 through which a supply of external air maybe admitted to pass through the pul-l verizer with the coal, which air supply 1s controlled byl a -damper 22. Similar y an aperture 23 1s provided in the other pedestal 4 through which a supplementary supply of lexternal air may be admitted and controlled by a damper 24.- to regulate the draught of the fan 12 through the pulverizer, and the amount of air delivered with IThe cavities of the pedestals 3 and 4 are not only in communication with the pulverizer casing and the fan casing respectively, but are connected to the space within the base 2, to which space air is supplied which has been heated in any convenient manner by the waste heat from the furnace. Prefer- 10 ably the base 2 is secured on a hot air flue F with which it is in communication, as shown in Fig. 1. j

Dampers 26 and 27 are slidable across the apertures between the base 2 and the pedestals 3 and l by which dempers the amount of heated air admitted to the pulverizer and the fan may be regulated to what is required. The shaft 5 on which is secured the fan 12, the pulverizing wheels 11 and the conical rimmed wheels 13, is driven at a suitable speed of rotation from any convenient source of power, either as shown by a belt over a pulley 25 and the coal feed screw 18 is rotated at a relatively low speed of rotation by any convenient means from the shaftp that will aHord facility for regulating the amount of coal delivered to the pulverizer. In the drawing it is shown as operated by a pawl v3() on the end of a radius arm 3l mounted to move freely on the shaft 28 of the feed screw 18 and engage the teeth of a ratchet wheel 29 secured on the same screw shaft to rotate with it. vThe pawl lever 31 is oscillated through a definite arc of movenarrante portion 37, concentric with and lprojecting1 across the toothed edge of the ratchet wheel 29, which, as moved to or from the pawl 30,

will determine the number of teeth engaged by the awl.

rlhis ever 36 and arcuate shield 3'? ma be moved by a rod 42 to control the coal fee either .by hand or automatically, by the steam pressure of ,the boiler or b the temperature-of the gases as delivere from the furnace or to the smokestack.

The dempers 22, 24 may be adjustably connected by'rods 38,41 lto the control arm 3'( of the coal feed mechanism that the amount of air admitted may be varied with the amount of coal fed to the pulverizer.

The coal to be pulverized, previously broken to a suitable size, is continuously fed from -the hopper 19 and delivered through the chute'17 into the space 16 within the cylindrical bushing 15 and passes therefrom through the conical wheel 13 at that end of the pulverizer. wheel 13 it is thrown violently outward by centrifugal force into the space between the lining rings 8 and the wheels 11, which space is swept by thepins 10 projecting from the wheels. l

Through this space it is carried by the draught from the fan 12 and is eectively broken into a line powder, as the centrifugal tendency throwsit into the spaces between the ridges 9 of the 'rings which spaces are more closely swept by the ends of the pins As soon as' the coal is pulverized to a degree of fineness that it is held in supension in the air, the draught of the fan draws it with the air and delivers it through the fan discharge 2O for delivery to the furnace.

Particular' attention is drawn to the important part played by the oppositely coned wheels 13.l rlhe arms of these wheels have a blade area little, if any, inferior to that of the fan blades and they travel at the same velocity, so that ,they exercise a considerable centrifugal effect on'the air with which they come in contact. The rims of these wheels 13 being oppositely coned to direct the air delivered from them .into the pulverizer, their effect will be to counteract one another and retain the coal within the scope of the beaters until it is suiiiciently .fine to be carried away by the preponderating draught due to the fan 12.

The dampers 22 and26 aEord full control of the amount of air delivered with the fuel to the pulveri'zer and the temperature of the air soadmlt-ted and the dempers 24 and 27 control not only the amount of air to be As it passes through the y delivered with the fuel to the furnace and its temperature, but regulate the drauglht through the pulverizer and therefore the egree of fineness to which the fuel isV reduced, and these air controls may be co-ope'rative with `the fuel control.

It must be noted that the pulverizing is effected by the impact ofthe arms of the wheel 13, and the radially projecting pins on the coal, and by the coal against the corrugations of the lining rings 8, and not in any way by direct crushing.

It must be distinctly understood that the flow of air by which the pulverized fuel is separated from that vnot sufficiently pulverized may supply suiicient air to satisfy the requirements of combustion, but if' not a further supply of air may be furnished at or I adjacent the delivery of the pulverizedfuel and air to the furnace.

vI do not desire to be confined to the particular arrangement and construction of the parts as described and illustrated as the structural features may vbe varie l within' wide limits without departing from my invention: Thus', while the drawing shows a number of lining rin s and a corresponding series of pinned whee s rotatable in proximity to them, it is believedthat this number may be considerably reduced without impairing the efficiency of the machine as al l pulverlzer.

A considerable proportion ofthe energy applied to effect the pulverization naturally causes an increase in temperature of the air within the pulverizer, which together with the'heated air admitted through the dampers 26 is suflicient to evaporate the moisture from the coal, and as the coal and air are delivered direct to the furnace the energy so spent is not wasted.

Having now particularly described my invention, I hereby declare that what I claim as new and desire to be protectedi in by Letters Patent, is: Y

1. A means for pulverizing coal or the like material and for delivering it for-combustion, said means comprising a rotatable body having projections on its periphery, a spoked wheel at each end of the rotatable body and rotatable with it, eachwheel hav,- ing a rim which is conically reduced from approximately the diameter of the rotatable body and its projections, a casing enclosing the rotatable body and conforming closely to the space swept by its projections and the conical rims of the wheels rotatable with it said casing having projections interspaced with those vof the rotatable body, means for delivering'the coal to be pulverized lwithin the conical rim ofthe wheel at one end of the rotatable body, means for delivering a controlled supply of airlwith the coal, means for withdrawing from the other end of the casing the air with such coal dust asis held in suspension' with it and for deliveringit outslde of said casing, and means for varying the draught of air through the casin 2.v means for pulverizing coal or the like material and forA delivering it for combustion, said means comprisin `a series Jof disc wheels secured on a rotatab e shaft with thedisc surfaces a short distance apart, saidV discs having pins radially projecting from their periphery, a spoked wheel secured at each end` of the series of discs to rotate with deliverin a supply of air to the same, means for with ra'wing the air with such of the coal as is held in suspension with it through the other end of the casingI and for delivering it outside of said casing, and means for varying the draught of air so withdrawn.

3. A means for pulverizing coal orv the like material and for delivering it for combustion, said means comprising a rotatable body having pins radially projectingfrom its outer surface, said pins bein bent to a U-shape with the bend cast in t e body, a casing conforming closely to the sweep of the projections and having projections interspaced Vbetween those of the rotatable body, means for delivering the coal to be pulverizedv within one end of the casing, means for admitting airto the same end of the casing, means for withdrawing the air from the other end of the casing with such of the pulverized coal as is held in suspension with it and for delivering it outside of said casing. l

4. A means for pulverizing coal or` the like material and for -deliveringit for combustion, said means comprising a series of disc wheels secured on a shaft, each wheel having pins radially projecting from its periphery, the pins beingbent to a U-shape with the bend cast in the rim of the wheel,

a spoled wheel secured on the same shaft at each end of the serles of discs, each wheel having a conical rim the larger end of which 'extends from adjacent the outer ends of the pins, a casing having a cylindrical portion around the disc wheels, and conically reduced therefrom to conform closely 'to the conical rims of the spoked wheels, a series of rings fitted within the cylindrical v portion of the casing, each ring projecting inward between the pins of the several discs, the inwardly projectlng portion of each ring being corrugated around its inner circumference and around its sides, means for delivel-ing the coal to be pul-verizcd within the smaller end of `one of the conical, rimmed Wheels, 'means for supplying air to the same end, means for withdrawing the air from the other end of the casin of the pulverized coal as is helv in suspension with it and for delivering it outside of said casing, and means for Varying the draught of the air so withdrawn.

5. A means for pulverizin'g coal or the like material and for-delivering it for combustion, said means comprising a rbtatable body having projections from its periphery, a casing closely conforming to the space swept by the projections of the rotatable body, means co-operative with rotation ofl the bodyfor delivering the coal to bepulverizedY into one end of the casing, means for varying while the machine is running the amount of coal so delivered, means for delivering a supply of air to the same end of the casing, means co-operative with variation of the coal feed for varying the amount of air so admitted, and means for withdrawing the air fromthe casing with such of the coal dust onlyv as is held in suspension with it, and for'delivering .it with the coal dust for combustion. l

6. A means for pulverizing coal and for -delivering it -with air for combustion, said means comprising aseries of 'disc wheels secured on arotatable shaft with their disc surfaces a short distance apart, each wheel having pins radially projecting from its periphery, a spoked wheel secured on the same shaft adjacent each end disc of the series., each spoked wheel having a rim which is conically reduced from approximately the diameter swept by the pins of the discs, a casing enclosing the discs and the conically rimmed wheels and conforming closely co-the space swept by them, said lcasing having rims projecting into the spaces between the pins of adjacent discs the inner surfaces and sides of said rings being corrugated, means vco-operative with rotation of the shaft for feeding the coal to be pulverized within the smaller diameter of one of the lconically rimmed wheels, means for regulating the -amount of coal feed, means for.' admitting a supply of heated air with the coal to be pulverized, means for admitting a supply of external air to the same, means co-operative with the `coal feed for varying the amount of with suchv cause the coal Leraar/e verizer, and means for admitting a con-v to the same through the trolled supply ofexternal air whereby the draught of air pulverizer ma be varied.

7. 'ln Ta coa pulverizing machina'means for pulverizing coal, means for admitting an.' into the pulverizing means, means for withdrawing the pulverized coal and air from the pulverizi'ng means it outside of the apparatus, maticall fed to t e pulverizerl andmeans for simultaneously controlling theamount of air permitted to pass through thepulverizer, substantially as shown and described.

8, In coal pulverizer, means for pulverizing the coal, means forpassing an air stream throueh said pulverizing means to dust to passwith kair stream out of the pulverize'r, meansfor controlling the amount of coal fed to the pulverizer, means for controlling the amount of'air admitted to the pulverizerto constitute the means for autolair stream that passes through the pulverize'r, and means for automatically actuating said coal controlling means and said air admissioncontrolling meansl inA cooperation.

9. A mechanism for pulverizing coal or the like and delivering it for combustion,

said. mechanism comprising a' rotatable pulverizer body having projections on 'its periphery, a casing closely conforming to the space swept by the projections of the rotatable body, said casing having an inlet at one end and an outlet at the other end, means. for admitting fuel into the inlet end of said casing, a suction fan connected with and delivering controlling the amountv of coal ieu the outlet end of said casing for creating a suction from .the inlet to the outlet end of said casing and delivering the air and nely divided coal from the fan outlet, means for admitting air to the inlet end of the casing,

an independentmeans for admitting airto the suction fan and automatically controlled dampers for said air admitting means cooperative with the fuel supply substantially as shown and described.

ln testimony whereof I allix my si FRANK SAWF RD.

ature.. 

